Indicator



Aug 25, J. J. BOLTON, JR., ETAL INDICATOR Filed Dec. 2, 1941 2Sheets-Sheet 2 -mmw/@wm Patented Aug. 25, 1942 UNHTIED fr fi;

NDICATGR Appiication December 2, 1941, LScrialNo. 421,336

8 Claims.

This invention relates to indicators and is more particularlyconcernedwith devices for renderingzavisualindication of the extent ofangular displacement of a rotatable shaft from a predetermined point.

In many'typesof: apparatus control of necessary-adjustments is effectedthrough the manual rotation of a shaft connected to a handwheel or thelike. Since,r in effecting such adjustments, the `operator may bevrequired to overcome considerable resistance, gear reductions arefrequently Anecessary to afford mechanical advantage with theresult/"that an angular displacement of the control shaft considerablyin excess of 360 may be required in order `to bring about a desiredchange in position ofxthe controlled element. As a consequence of suchrelatively greatamplitudes ofangular displacement on the part -ofcontrol shafts, indicators associated therewith cannot be directlyconnected, since after 360 of movement, any type of scale calibrationwill begin to repeat with resulting confusionon the part of theoperator.

Of course, solutions to the foregoing problem have long been known anditis now customary to provide gear lreduction systems to the end that theindicator may move to anextent proportional to the extent of angulardisplacement of the control shaft but may havea reduced amplitude-ofmovement. Such arrangements are satisfactory within certain limitswhere, for instance, the total movement ofthe control shaft isrelatively small, i. e., a very few turns, or where the space occupiedby the gear reduction system is of little moment.

Gear reduction systems as at kpresent known are not, however,satisfactory when employed with shafts which must have relatively greatamplitudes of angular displacement and which must be positioned inlocations where space is at a premium. While it will be recognized thata number of such situations arise vin the industrial world, a particularproblem has been encountered in conjunction with the various remotecontrol systems used in navel vessels. In such instances, accuracy ofindication and reliability must be, without impairment, correlated withcompactness.

The problem encountered in fitting out naval vessels has been recentlystill further complicated by the employment of airplane hoist equipmentallowing catapult launched planes to be raised toa ship deck from aSeaway. Since such equipment is normally operated through hydraulictransmissions, the stroking of which must (Cl. liti-+1124) bermostIaccurately controlled from a station on the' bridge, it is evident. that.an accurate indicater must vbe associated with'the control handwheelforthe guidance of the operator and that, in this situation, conventionalgear reduction systems vof suitable accuracy arewholly unsatisfactorybecause of their space requirements.

It isthereforean object of this invention to solve theforegoing problemsand to provide a sturdy` andcompactindicator system in association witha rotatable shaft which will render accurate indications of extent ofangular displacementof such shaft.

vAccording to thisV invention it is contemplated that the indicator lbemovable in the direction of the shaft with'which it is associated at arate and to an extent proportional to its angular displacementl andthatit be readily adaptable to -a widevariety of requirements las regards tototal amplitude of rotative movement of a control` shaft.

@ther objects andpadvantages of the invention Ywill Ybe apparent from aconsideration of the following detailedr description of a preferredembodiment thereof in conjunction with the annexedvdrawings wherein:

`Figure l lisa top plan view of a control handwheel ,and associatedindicator system applied to'. the remote control station for theoperation of the A endcf a hydraulic transmission;

Figure2 is a View in vertical section taken along `the line 2 2 ofFigure 1;

Figure- 3 is a View `in section taken along the line` of-'Figure 2; and

Figure 'Ll is a vertical sectional view taken along the line i-toffigure 2.

Referring more specifically to the drawings, the device consists of ahandwheel l0 keyed at iiV to a shaft i2 which in yturn extends directly,

or through universal joints, to the adjustment spindle cfa hydraulictransmission, not shown.

`By rotation of shaft l2 the delivery speed of the hydraulictransmission may be varied from a neutral position to a full speedposition in either direction. YTo adjust from neutral to full speedusually requires some 2 revolutions of shaft l2, varying more lor lessaccording to the type of apparatus operated.

Since in the hoisting of seaborne aircraft it is essential that thecontrol be as accurate as possiblev and that the cperatorbe fullyapprised of the position of the transmission adjustment spindleat-alltimes, an indicator arm I3 is associated with shaft l2 to indicateangular displacement -thereof on a plaque lli havinga calibrated scale.This scale may, of course, be calibrated directly in degrees of angulardisplacement of shaft I2 or may bear suitable designations as to whatconditions are brought about at any predetermined angular positionthereof. Thus, the angular displacement of shaft I2 is indicated by therelative positions of indicator arm I3 and stationary plaque I4. Clearlythis arrangement could be reversed, and by driving the plaque andmaintaining the indicator arm stationary the same results can beattained.

To bring about movement' of indicator arm I3 to an extent proportionalto that of shaft I2, the connections shown in Figures 2, 3 and 4, areemployed. These comprise chiefly a sleeve I5 driven axially by shaft I2to an extent proportional to the angular displacement of the latter andfollowers I6 disposed in helical grooves I1 of said sleeve fortransmitting its axial movement in the form of angular displacement ofindicator arm I3. So that sleeve I5 may be driven axially of shaft I2 itis interiorly triple threaded, as indicated in Figure 3, for cooperationwith a triple threaded Zone extending axially of shaft I2. The merethreaded engagement of sleeve I5 and shaft I2, would not, of course,result in proportional relative axial movement, it being necessary tohold sleeve I5 against rotation in order that it may move axially inresponse to rotation of shaft I2. In this connection it should be notedthat sleeve I5 is not extericrly cylindrical, but is provided with twoparallel flattened zones I8 extending chordwise thereof for the entireaxial length. These zones cooperate with inwardly extending arms I9 and20 integral respectively with vertically extending members 2| and 22which are integral with and extend upwardly from an annular member 23having an outwardly extending annular flange 24 and an inwardlyextending annular ange 25.

Annular member 23, and hence its integral parts I9, 20, 2| and 22, isheld against rotation by connection of its flange 24 to a concentricsleeve 2S provided with an annular flange 21 overlying and connected tostationary plate 28, which, as shown in Figure 1, is the cover plate forthe instrument housing at the control station. It is this plate 28 whichalso carries, fixedly attached thereto, calibrated plaque I4, the latterbeing disposed in an arc corresponding to the path of movement ofindicator arm I3.

In addition to the stationary parts just mentioned a cap 29 'is providedfor the purpose of assisting in the support of ball bearings 30 forshaft I2. This cap is connected by four bolts 3| which are driven intothreaded sockets in the bottom of sleeve 26, flange 24 being alsoprovided with registering bolt holes so that it may be held between themarginal portion of cap 29 and the bottom edge of sleeve 26. Cap 29 isprovided with an annular shoulder 32 the upper edge of which cooperateswith flange 25 of annular member 23 to hold outer portion 33 of a racefor ball bearings 30. Inner portion 34 of said race is held from shaftI2, the latter being provided with an annular flange 35 contacting theupper surface of portion 34, While a washer 36 is drawn against thelower surface thereof. Washer 36 is held in position by a nut 31 inthreaded engagement with a portion 38 of shaft I2. Balls 30 thusconstitute both a radial and an axial thrust bearing for shaft I2.

Having now described the stationary portions of the apparatus and themanner in which they serve to prevent rotation of sleeve I5 and supportbearings for shaft I2, the movable portion of the device will bediscussed. This consists of a sleeve 39 mounted concentrically overshaft I2 and sleeve I5 but extending within sleeve 26. Indicator arm I3s integral with and extends radially from sleeve 39 for rotativemovement in a plane parallel to but above the plane of plaque I4.Movement is imparted to this sleeve through axial movement of sleeve I5which will cause angular displacement of pins I6 which, as can be seenin Figure 3, extend radially inwardly from socket in sleeve 39 intohelical grooves I1. Antifriction roller bearings 40 disposed in a race4I facilitate this movement.

The remaining structural details of the apparatus comprise oil seals 42,43 and 44 and plugs 45 and 46, through which a suitable lubricant may besupplied. Additionally it should be noted that flange 21 of sleeve 2G isprovided with elongated slots 41 for the reception of bolts 48 whichserve to fasten the flange to the edge of plate 28 which defines theopening for shaft I2 and the associated parts. Because of the provisionof slots 41, the stationary portions of the equipment supported fromsleeve 26 may be initially placed in the exact angular position desiredafter which bolts 48 may be tightened to maintain the adjustment.

The operation of the apparatus just described is now evident. Uponrotation of shaft I2 through handwheel I0 to effect an adjustment of theelement under the control of said shaft, sleeve I5 will be moved eitheraxially upwardly or downwardly depending upon the direction of rotationof shaft I2. Since the connection involves helical screw threads, it isapparent that the axial movement of sleeve I5 per degree of angulardisplacement of shaft I2 will be constant, having an amplitude dependentupon that of the helix angle or pitch of the threads. Thus, by variationin the pitch of the threads connecting sleeve I5 and shaft I2, increaseor decrease in the axial displacement of sleeve I5 per degree of angulardisplacement of shaft I2 is possible.

Th'e foregoing, however, is not the only speed reduction factor affordedby the present invention, for sleeve I5 is provided with oppositelydirected helical grooves I1, apart, from which projections I6, and hencesleeve 39 and indicator arm I3, are driven. It is therefore clear that avariation in the helix angle of grooves I1 will have the effect ofincreasing or decreasing the angular displacement of indicator arm I3per unit of axial movement of sleeve 25. Thus, with a helix angle of 9.7degrees in the threaded connection between sleeve I5 and shaft I2 and ahelix angle of 61.305 degrees for grooves I1, it is possible to effectan 20.572 to one ratio between shaft I2 and indicator arm I3.

Although the form of the invention just described is concerned with anapplication thereof to the control of an A end of a hydraulictransmission, it is apparent that the invention is of wide applicabilityin indicating the rate and extent of angular displacement of any shaft.

We claim:

1. A device for indicating the extent of angular displacement of a shaftcomprising, means movable by said shaft axially thereof to an extentproportional to that of its angular displacement, and relativelyrotatable indicating elements, one of said indicating elements beingdisplaced with respect to the other of said elements by said means to anextent proportional to the axial displacement thereof, the axis ofrotation of the aacute element which is displaced being also the axis ofthe shaft.

2. A device for indicating the extent of angular displacement of ash'aft comprising, means movable by said shaft axially thereof to anextent proportional to that of its angular displacement, relativelymovable indicating elements, and means coaxial of said shaft responsiveto movement of said axially movable means for effecting Vangulardisplacement of one of said indicating elements with respect to theother of said elements to an extent proportional to such axial movement.

3. A device for indicating the extent of angular displacement of a shaftcomprising, means movable by said shaft axially thereof to an extentproportional to that of its angular displacement, an indicator arm, acooperating scale, and means coaxial of said shaft for effecting angulardisplacement of said arm relative to said scale to Aan extentproportional to the extent of axial displacement of said axially movablemeans.

4. A device for indicating the extent of angular displacement of a shaftcomprising, means surrounding said shaft and adapted to be moved therebyaxially thereof to an extent proportional to that of its angulardisplacement, means surrounding said rst named means adapted to beangularly displaced to an extent proportional to the extent of axialdisplacement of said rst named means, an indicator carried by saidsecond named means, and stationary means in registry with said indicatorto afford a basis for determination of the amplitude of relativedisplacement of said indicator and said stationary means.

5. In a construction including a rotatable handwheel and a coactingindicator arm and scale for indicating the amplitude of movement of saidhandwheel, a threaded shaft driven by said handwheel, a sleeve threadedon said shaft, said sleeve h'aving a surface groove therein disposed atan angle to its long axis, a follower disposed in said groove andconnected to said indicator arm, and means for holding said sleeveagainst rotative movement, whereby said follower will be subject toangular displacement which is imparted to said indicator arm uponrotation of said handwheel.

6. In a construction including a rotatable handwheel and a coactingindicator arm and scale for indicating the amplitude of movement of saidhandwheel, a threaded shaft driven by said handwheel, a sleeve threadedon said shaft, a helical groove in the external surface of said sleeve,a follower disposed in said groove and connected to said indicator arm,and means for holding said sleeve against rotative movement, wherebysaid follower will be subject to angular displacement to an extentproportional to the extent of axial movement of said sleeve which inturn is proportional to the extent of angular displacement o-f thehandwheel.

7. In a construction including a rotatable handwheel and a coactingindicator arm and scale for indicating the extent of angulardisplacement of said handwheel, a shaft extending axially of thehandwheel and rotatable therewith, a sleeve mounted over said shaft foraxial movement with respect thereto, said sleeve being interiorlythreaded and said shaft being provided with cooperating threads for aportion of its length in excess of the length of the threaded area ofsaid sleeve, said sleeve -also being provided with a helical groove, asecond sleeve surrounding said grooved sleeve having the indicator armextending radially therefrom, a follower extending inwardly from saidsecond sleeve into the groove of the grooved sleeve, and stationarymeans including bearings for said shaft and said second sleeve and meansfor holding said grooved sleeve against rotative movement, wherebyangular displacement of said shaft will result in proportional movementof lesser amplitude on the part of the indicator arm.

8. In a construction including a rotatable handwheel and a coactingindicator arm and scale for indicating the extent of angulardisplacement of said handwheel, a shaft extending axially of thehandwheel and rotatable therewith, a sleeve mounted over said shaft foraxial movement with respect thereto, said sleeve being internallythreaded and said shaft being provided with cooperating threads for aportion of its length in excess of the length of the threaded area ofsaid sleeve, said sleeve having diametrically opposed attened areas andbeing provided with two oppositely directed helical grooves disposedapart, a second sleeve surrounding said grooved sleeve and h'aving theindicator arm extending radially therefrom, followers extending inwardlyfrom said second sleeve into the respective grooves of the groovedsleeve, whereby the axial movement of said grooved sleeve causes anangular movement of said second sleeve, and stationary means includingbearings for said shaft and said second sleeve and means acting on theilattened portions of said grooved sleeve to hold the same againstrotative movement, wh'ereby angular displacement of said shaft willresult in angular movement of lesser amplitude on the part of theindicator arm with respect to said scale.

JAMES J. BOLTON, JR. THOMAS SYKES.

